Hydrochloric Acid → 3-Amino-2,6-dichlorobenzoic acid

Temperature

60 °C

2,6-Dichloro-3-nitro-benzoic acid (10 g, 42 mmol, Step a) was added to concentrated hydrochloric acid (100 mL) followed by stannous chloride dihydrate (38 g, 169 mmol). The reaction mixture was heated at 60° C. for 1 hour. The reaction mixture was diluted with water (500 mL) and extracted with ethyl acetate (2×300 mL). The combined organic layer was dried over anhydrous sodium sulphate and concentrated under vacuum to afford the sticky material. The sticky material (crude product) was dissolved in water (turbid solution, 200 mL) and treated slowly with aqueous sodium hydroxide (20%) solution till precipitation while maintaining the pH 1-2 (dense precipitate was observed). The precipitate was filtered and the filtrate was extracted with ethyl acetate (2×200 mL) and dried over anhydrous sodium sulphate and concentrated under vacuum to yield 3-amino-2,6-dichlorobenzoic acid as a creamish solid (6 gm, 69%).

1. extractionextracted with ethyl acetate (2×300 mL)
2. dry with materialThe combined organic layer was dried over anhydrous sodium sulphate
3. concentrationconcentrated under vacuum
4. customto afford the sticky material
5. temperaturewhile maintaining the pH 1-2 (dense precipitate was observed)
6. filtrationThe precipitate was filtered
7. extractionthe filtrate was extracted with ethyl acetate (2×200 mL)
8. dry with materialdried over anhydrous sodium sulphate
9. concentrationconcentrated under vacuum

ORD record

ord-77bccc2e8d824f98b6aadd1d0847cc21

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08980911B2